Ishwar S. answered 07/15/18
Tutor
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University Professor - General and Organic Chemistry
Hello Arshad
First let's write the balanced chemical reaction between ammonia and oxygen
4NH3 (g) + 5O2 (g) → 4NO (g) + 6H2O (g)
Since the masses of NH3 and O2 are given, we need to first determine which of them is the limiting reagent. The limiting reagent will be completely consumed in the reaction, and the amount of product (NO) formed will depend on this value.
For NH3 as the reactant, the stoichiometry process is g NH3 → mol NH3 → mol NO. Molar mass of NH3 = 17 g/mol. From the balanced reaction, 4 moles of NH3 reacts to form 4 moles of NO.
68 g NH3 x (1 mol NH3 / 17 g NH3) x (4 mol NO / 4 mol NH3) = 4.0 mol NO
For O2 as the reactant, the stoichiometry process is g O2 → mol O2 → mol NO. Molar mass of O2 = 32 g/mol. From the balanced reaction, 5 moles of O2 reacts to form 4 moles of NO.
192 g O2 x (1 mol O2 / 32 g O2) x (4 mol NO / 5 mol O2) = 4.8 mol NO
192 g O2 x (1 mol O2 / 32 g O2) x (4 mol NO / 5 mol O2) = 4.8 mol NO
Since NH3 forms less NO than O2, NH3 is therefore the limiting reagent. The amount of NO formed in this reaction is 4.0 moles.